Brazing alloy



United States Patent US. Cl. 75-134 2 Claims ABSTRACT OF THE DISCLOSUREA cadmium, copper and zinc containing silver alloy with less than 40%but at least 30% by weight of silver wherein said copper and zinccontents of the resultant reduced silver alloy are determined by thefollowing formulae:

Resultant Cu by wt. percent=l9+.8 (40Ag content by wt. percent)Resultant Zn by wt. percent=22+.2 (40Ag content by wt. percent) andwherein the copper content of the resultant alloy varies i-l.5% byweight and wherein the zinc content of the resultant alloy varies i.5%by weight, wherein the balance of said alloy is cadmium.

3,539,339 Patented Nov. 10, 1970 ice position while maintainingessential properties only where the silver content of the referencealloy is reduced between 29 and 39% silver by weight.

In addition, experimentation revealed that the desirable properties aremaintained in this class of alloys and this concept is applicable wherethe copper content of the resultant alloys, as indicated by the outlinedmathematical formula, ranges plus and minus 1.5% by weight in the broadrange and plus and minus 1% by weight in the preferred range and wherethe zinc content indicated by the formula ranges plus and minus .5% byWeight in the broad range and plus and minus .3% by weight for thepreferred range.

A sampling of the numerous alloy compositions that were tested is asfollows:

Composition by weight percent Ag Cu Cd Zn The foregoing alloy sampleswhen tested revealed the following results:

This invention relates generally to silver alloys and more particularlyto silver alloys with reduced silver con tent but which have the sameessential basic properties as alloys with higher silver contents.

Heretofore it has been known that silver alloys containing silver andwith additions of copper, zinc and cadmium of approximately 20% each byweight have solidus and liquidus temperatures, tensile strength, shearstrength, plasticity and surface Wetting characteristics that are mostdesirable in various welding processes such as brazing. For some timeexperiments have been conducted to develop silver alloys of this generaltype with reduced silver content but which would retain the foregoingoutlined characteristics so essential in the application of thesealloys.

After lengthy experimentation with various alloy systems it wasdiscovered that within a particular zone range of the silver, copper,cadmium and zinc alloy system, Where cadmium is maintained at a range ofapproximately 18 to 21% by weight, the essential properties of the alloysystem with 40% by weight silver, are maintained in alloys of the samesystem where silver is reduced provided the copper and zinc contents ofthese alloys are increased in accordance with the following formulae:

Resultant Cu by wt. percent=l9+.8 (40Ag content by wt. percent)Resultant Zn by wt. percent=22+.2 (40Ag content by wt. percent)Experimentation further revealed that the above outlined concept isvalid in determining changes in alloy com- It will now be understood bythose skilled in the art that the objects of this invention have beenachieved by providing a formula for the reduction of silver in silveralloys while maintaining at reasonable constancy the essentialproperties of the high silver content silver base alloys.

What is claimed is:

1. A cadmium, copper and zinc containing silver alloy consistingessentially of 37.5% silver, 21% copper, 22.5% zinc, balance cadmium.

2. A cadmium, copper and zinc containing silver alloy consistingessentially of 35% silver, 23% copper, 23% zinc, balance cadmium.

References Cited L. DEWAYNE RUTLEDGE, Primary Examiner G. K. WHITE,Assistant Examiner US. Cl. X.R. -173

